The proposed jetty was to start from the north side of the Saint Jones entrance, with a direction nearly east, and after crossing the 2-foot lowwater contour, to curve to south and east, with a total length to the 3-foot low-water contour in the bay of about 3,300 feet.

The cost of the jetty and of the necessary dredging to make a 3-foot channel 100 feet in width was $35,000. To extend the jetty to the 4-foot low-water curve, with corresponding additional dredging, would cost $42,500.

Were the improvement of the Murderkill entrance only in question, the project and estimate would be almost exactly the same as those given for Saint Jones.

Since, however, the mouths of the two streams are at a less distance apart than that to which the projected works for either would extend into the bay, and since the improvement of the Saint Jones has already been appropriated for, and is under consideration by Congress, it becomes necessary to combine the two projects in order both to avoid injurious interference, and, if practicable, to secure more advantageous results.

Upon the accompanying chart of the entrances to the two creeks two projects for their combined improvement are shown, marked, respectively. A in red and B in blue lines.

The leading feature of project B (which is an ingenious suggestion by Mr. Gieseler) is to unite, by means of concave half dikes of suitable radius, the effluent waters of the two streams, in the anticipation that their combined volumes may suffice to erode a channel across the flats on the prolongation of their common tangent, which has a direction such as not to interfere with the free admission of the flood-tide into both.

Good results may reasonably be expected from this project, which furthermore admits of future extension and attainment of greater depths by the construction of dikes beyond the point of tangency and parallel to the sides of the exterior channel.

The large amount of excavation required, however, makes the cost considerable, and the project is liable to the further objection that no provision is made for the securing of harbor space.

Project A, shown in red lines, includes the dike hitherto projected for the Saint Jones entrance, the position and development of which, owing to the circumstances of the case, admit of no material variation. The position of the Murderkill dike, however, may be varied in the manner to be hereafter determined as most favorable regarding results and

costs..

Three positions are shown on the chart, marked A1, A2, and A3.

The first maintains a concave bend throughout its length and gives the most harbor space; the second affords a better entrance for the flood-tide; while the third more nearly unites the two streams, but largely diminishes the area of the harbor. By reason of the greater amount of dredging necessary, it is, besides, much the most expensive of the three.

Estimating on the basis of a low-water entrance depth of 4 feet, the cost of the several projects, including dikes and dredging, is computed as follows:

To the above amounts should be added the 12,000 estimated as necessary for the dredging in the bed of the Murderkill between Webb's Landing and the mouth.

The estimates above given are for a 4-foot low-water entrance.

It is not necessary that the entire amounts should be given at any one time, nor need the depth estimated for be necessarily adhered to.

An increase of the present depth to 3 feet at low-water, or even a reliable entrance, fixed in position, of 2 feet would be of great value to the navigation and trade of both streams. To effect these, a nearly proportional reduction in the estimate may be made of 25 per cent. for each foot of draught surrendered. Thus, taking project A as a basis, to obtain 3 feet would cost about $55,000, and for 2 feet about $40,000.

The argument as to the propriety of the expenditure of these amounts depends less upon the present trade of the streams in question than upon its probable development, when by the opening of the mouths reliable access may be had to the interior.

The construction of harbors of refuge for the numerous small vessels navigating the bay is likewise a matter worthy of consideration. Respectfully submitted.

The CHIEF OF ENGINEERS, U. S. A.

WILLIAM LUDLOW,

Captain of Engineers,

Brt. Lieut. Col., U. S. A.

REPORT OF MR. E. A. GIESELER, ASSISTANT ENGINEER.

UNITED STATES ENGINEER OFFICE,
Philadelphia, Pa., March 4, 1882.

COLONEL: I have the honor to report as follows upon the examination of Murderkill Creek:

The examination extended over that part of the creek lying between Quillen's Landing, 5 miles above Frederica, and the mouth, a total distance of about 124 miles, measured on the water.

The field-work was executed between the 19th and 27th of October, 1881. The turnpike bridge above Frederica not being permanent, but a draw allowing the passage of vessels, Frederica, strictly speaking, cannot be called the head of navigation. Yet that term is applicable to the place mentioned, since the trade above it is very small. In view of this fact and of the limited means at disposal for the examination, and considering the sufficient depths from Quillen's Landing to Frederica (54 feet at high-water), obstructed slightly in two places only, it was thought sufficient merely to examine these shoals and to omit that detailed examination of the upper creek which would have been necessary for subsequent mapping. The chart, therefore, does not show the upper 5 miles of the creek above Frederica.

This course appeared the more desirable since the original intention of confining the field-work to the collection of hydrographical data only had to be abandoned, the very first exploration developing the unreliability of the creek lines as shown in the atlas used as a basis for the topography. It was found impossible to locate the lines of soundings by reaches and points as given on this map, because hardly any of them could be identified in the field, and the range of the necessary field-work was thus unexpectedly widened at the outset.

A rapid polygon was run from Frederica down to the mouth, the angles of which were taken by sextant, and the distances measured by means of a telameter rod, while cross-lines were located and sounded at suitable distances and the existing shoals examined as to their extent and material. From work like this, that lies between "field-sketching" and "surveying," no great degree of exactness can be expected, but merely that reasonable accuracy which is sufficient for the practical purposes in view.

Two tide-gauges were established, viz, one at the mouth and one at Frederica. The one at the mouth was established on the same level as the one that had been used

during the preceding survey of the mouth of Saint Jones, thus allowing the use of previous observations in computing the tidal element. Even including those former observations, the entire amount of data available is small, and as simultaneous observations on a standard gauge were not practicable, the results arrived at in regard to the tidal conditions of the creek are necessarily only approximate. According to these it appears that mean rise and fall at the mouth is 4.2 feet, while at Frederica it is about 1.2 feet, or 3 feet less.

The distance from the mouth to Frederica, 7 miles, seems to be traversed by the high-water in somewhat more, and by the low-water in somewhat less, than three hours.

The greater part of the course of the creek is through marsh land at about the highwater level; here and there the ground rises a little more, and areas of farm land or high meadow stretch down to the banks. At the mouth a belt of sand, running along the beach, separates the meadow and marsh from the Delaware Bay.

A number of landings that are marked on the map are convenient shipping points for the products of the farms bordering on the creek, and, combined with the mercantile and manufacturing interest of Frederica, indicate a considerable trade in timber, lumber, phosphate materials, canned fruits, farm truck, &c.

Ten vessels, trading to Philadelphia and New York principally, are owned on the creek. Further details concerning these matters are given in a subjoined table, based on information received from Governor Hall, of Delaware, and Mr. Anderson, of Frederica.

The general direction of the creek from Frederica to the mouth is northeasterly. The original course was an extremely sinuous one, the distance from Frederica to the mouth, as measured along the creek, being about 11 miles, while the air-line distance is only about 5 miles. During the last sixty years, however, the parties interested in the trade of the creek have straightened its course by the construction of six canals at various places, and the water distance has been reduced to abont 74 miles. The entire length of these cuts amounts to nearly 14 miles, cutting off three times that length of creek.

According to information received from Mr. Anderson, of Frederica, the cost of the Bradley Cut, 30 feet wide by 6 feet deep and 2,000 feet long, was $1,100, which would represent a rate of less than 10 cents per cubic yard of material actually removed. The cuts, however, are only 30 feet wide, and the excavated material could be thrown on the shore directly from the dredge without further handling. Basing an estimate on the above price, the entire amount expended on the cuts would have been about $5,000, besides an unknown amount paid to property-holders who were damaged by the excavation of the cuts. In addition to this, $2,000 were expended in an unsuccessful attempt to improve the mouth of the creek by dredging.

The canals or cuts are a peculiar feature of the creek. Having been constructed with the single idea of reducing the distance at the least cost, their effect, however satisfactory for the time being, can scarcely prove entirely beneficial in the course of years. Their width is pretty uniformly about 30 feet, and depth about 6 feet, giving à mean low-water cross-sectional area of about 180 square feet. Now, the mean crosssectional area of the creek proper at Frederica may be put at about 450 square feet, gradually increasing to about 700 square feet at the mouth. Manifestly, therefore, the capacity of the cuts is entirely insufficient for the accommodation of the body of water moving in the creek. It is perhaps in appreciation of this fact that the old course has everywhere been left open, but naturally it is undergoing a gradual process of shoaling and narrowing, which in some cases has proceeded so far as to almost close the old creek bed. This is notably the case at Walker's and Warren's cuts, which are the two oldest ones.

It may be assumed that, as this shoaling of the old creek advances and the entire in-and out flow is more and more restricted to the narrow and insufficiently capacious cuts, the tidal volume of the creek is correspondingly diminished. Although no reliable historical data on this point could be obtained, it is quite probable that the mean rise and fall in the upper sections has already been reduced through the action of the causes named. On the other hand, it appears safe to say that a suitable increase in the area of the cuts would be followed by an increase in the tidal volume; assertions which, if they are correct, would have an important bearing not only on the future of the creek itself, but also on any contemplated improvement of the mouth.

The following list, besides giving other data concerning the cuts, gives the crosssectional area which, according to the mean profiles of the creek, they shouli possess:

List of canals in Murderkill Creek, commencing at the upper end of creek.

Sq. feet.

Sq. feet.

180-200

480

Bradley's Cut

Walker's Cut.

Total.

9, 170, 27, 270

18, 100 !

The only serious obstacles to navigation are found in the lower part of the creek and at the mouth. Once above Webb's Landing, about 1 mile above the mouth, vessels carry 5 feet at low-water to Frederica, and about 44 feet thence to Quillen's Landing, which is sufficient to accommodate the present trade of the creek. A few places at which the channel is partially obstructed are enumerated in the following list, with estimates of the quantity of material to be excavated and probable cost of excavation.

Passing from these minor obstructions to the consideration of the more important ones, we find that a little below Webb's Landing, at a point about 1 mile from the mouth, the creek commences to widen, and becomes correspondingly shallow. The channel depth in this lower section from 6 feet gradually diminishes to 34 feet near the mouth. The entrance depth from Delaware Bay is about 1 foot: Three methods of removing this difficulty suggest themselves:

The first and cheapest method would be to dredge a channel in the present creek bed. The excavation of a channel 80 feet wide and 6 feet deep at mean low-water would require the removal of about 40,000 cubic yards of sand and mud, which, putting the price of excavation at 30 cents per cubic yard, would give a total of $12,000. The disadvantage of this method would be the considerable annual outlay that may be anticipated for the maintenance of the dredged cut, the great width of the creek and the oystering operations carried on in it not being favorable conditions towards the permanence of the work.

The second method would be to cut through the marsh from a point a little below Lindell's Landing in an almost straight line to the mouth, a distance through the marsh of about one-half mile. This would offer the advantages of still further reducing the distances and of avoiding the greater portion of the shoals in the lower part of the creek, thus giving a greater promise of permanence than the first-mentioned project. The disadvantage of this method would be the cost. A canal cut on the line marked on the map from a little below Lindell's Landing to the mouth, 110 feet wide by 6 feet deep, would require the removal of about 170,000 enbic yards of sand, mud, and marsh, the latter forming by far the greater part. At 20 cents per cubic yard this would cost $34,000.

Both of these plans allow the improvement of the mouth of Murderkill Creek to be combined with that of the neighboring Saint Jones Creek.

The third method of improving the creek would consist in cutting a channel through the marsh from a point about 1,500 feet below Webb's Landing in a northeasterly direction straight to the beach. This would have the advantage of entirely avoiding the objectionable part of the creek at less than half the expense of the last-named method. But this plan would at the same time involve the shifting of the mouth of

Normal cross

sectional area.

the creek, and can therefore only be carried out if the idea of combining the mouth improvements of Murderkill and Saint Jones is abandoned.

The decision, then, as to which of the above three methods should be adopted is dependent, in the first place, on the conclusions arrived at in regard to the improvement of the entrance, and, secondly, on the relative advantages and expense. The various methods of improvement present themselves thus:

A. FIRST METHOD.-IMPROVING PRESENT CREEK BED,

1. Excavation of channel 80 feet wide and 6 feet deep in present creek bed, 40,000 cubic yards, at 30 cents per cubic yard..

2. Removal of upper obstructions, 2,000 cubic yards, at 50 cents per cubic yard..

Total.......

B. SECOND METHOD.-CANAL FROM LINDELL'S LANDING TO MOUTH.

$12,000

1,000

13,000

2. 300 feet of dike to close old channel, at $5 a foot

3. Removal of upper obstructions as above

Total....

1. Cut through salt marsh from about Lindell's Landing to beach, 170,000 cubic yards, at 20 cents per cubic yard

$34,000

1,500

1,000

36,500

C. THIRD METHOD.-NEW ENTRANCE BELOW WEBB'S LANDING,

1. Cut through salt marsh from about Webb's Landing to beach, 80,000 cubic yards, at 25 cents per cubic yard

2. 150 feet of dike to close old channel, at $5 a foot.

3. Removal of upper obstructions as above

Total

$20,000

750

1,000

21,750

In conclusion, it remains to say that whatever plan of improvement may be adopted the widening of the old canals should ultimately be a part of it, as to all appearances this is the point upon which the future tidal condition of the creek depends. I am, colonel, very respectfully, your obedient servant,

Col. WILLIAM LUDLOW,

Captain of Engineers, U. S. A.

E. A. GIESELER,
Assistant Engineer.

COMMERCIAL STATISTICS.-ANNUAL TRADE OF MURDERKILL CREEK.

EXAMINATION OF FRANKFORD CREEK, FROM ITS MOUTH IN THE DELAWARE RIVER TO FRANKFORD AVENUE.

UNITED STATES ENGINEER OFFICE,

Philadelphia, January 25, 1882.

SIR: I have the honor to present herewith tracing and papers in connection with the examination of Frankford Creek, Philadelphia, made in pursuance of the river and harbor act of March 3, 1881.

The topography of the creek was mainly supplied by drawings kindly placed at my disposal by Mr. Samuel L. Smedley, chief engineer and